Pressure retaining core barrel



July-8, 1941. D. w. AULD ETAL PRESSURE RETAINING CORE BARREL Filed Aug. 29,v 1939 D RLPDM s UB T5 NW.W N E J Z VD NLS L7 IAA- T Ww DL Patented July A'8, 1941 UNITED STATES PATENT OFFICE 2,248,910 PRESSURE RETAINING CORE BARREL Donald W. Auld and Louis J.- Weber, Bartlesville, Okla., assgnors to Phillips Petroleum Company, a corporation of Delaware Application August 29, 1939,` Serial No. 292,525

(Cl. Z55- 72) 6 Claims.

This invention relates to a device for taking.

ferent structures through which the drilling advances and also for further knowledge as to the geological make-up of the sub-structure. When the drilling encounters a sand or lime area which gives a showing of oil or gas, it ,is always the practice to take a sample or samples of the structure and test these cores to determine the oil content of the structure. Other valuable data is collected from the cores and correlated which assists in the production of the Well.

Cores have been taken of structure passed through in drilling wells for practically as long as wellshave been drilled. Coring apparatus has been developed which not only takes longitudinal cores but lateral core shooting has reached a high state of development. Up to the present time no coring device has been developed which takes a core at the pressure which exists in the area where the core is located. This is desirable in that it gives a true picture of existing conditions in the oil well. If the Well hole is bailed dry, the volatile constituents will have a chance to escape up the well bore. If the drilling mud is allowed to remain in the hole, it may exert a pressure greater than the formation exerts and some of the drilling mud may Ago into the formation. The desirable mode of operation is to balance the formation pressure against the pressure exerted by the drilling mud. When the pressures are equal a truly representative core may be had which will show `the natural conditions in the formation. I

The advantages of the present invention over known methods are many and possessed of utility. By the conventional procedure a core is drilled from a formation using an open-ended core barrel. The lowertend of the core is exposed to the well drilling fluid and to any pressure which may exist in the hole.- By the conventional procedure then, the core may be drilled under high pressure, but as it isI raised to 'the surface of the ground the pressure gradually diminishes until the core is at atmospheric pressure only. Any volatile constituents of the cores contents which are not stable at atmospheric pressure are thus lost.

The pressure retaining core barrel of the present invention is designed to close -pressure tight at the bottom of the drilled hole after being loaded with the core. In this condition it may be brought to the surface of the ground, at formation pressure along with a sample of the uid found in the structure. Obvious advantages are thenthat no part of the hole sample or of the cores contents may be lost in bringing up the 'core barrel. Cores taken by this method Vwill have a wider range of usefulness and give more information concerning the structure and its contents than can be obtained from la core taken in the usual manner.

It is an object of the present invention to provide a means whereby core samples may be re-.' covered from an underground formation under the same pressure as exists inthe formation.

A further object is the removal and recovery of all materials which were in the core at the time it was drilled, and a sample of the fluid present in the drilling-structure.

A still further object isto provide means. at-

1 tached to the end of a drill stem which provides a receptacle for the core being drilled, which receptacle is closed pressure tight when the coring is completed and which is removed from the well by pulling the drill tubing from the well.

Other objects andadvantages of the invention will be apparent during the course of the following description.

In the accompanying drawing, forming a part of this specification, and in which like numerals 'are employed to designate like parts throughout the same; l

Figure 1 a central. vertical longitudinal section through the bottom of the drill stem and coring receptacle, i

lFigure 2 is aV cross-sectional view taken through the line 2-2 of Figure l, and- Figure 3 is a view lpartly in side elevation and partly in section showing the fishing assembly.

In the drawing, wherein for the purpose of illustration, is shown a preferred embodiment of our invention, the numeral l represents the landing sub of the drill stem which is made-up of sections and extends from the surface of the ground. Connected to the landing sub l by means of the adaptor 2 is the barrel member 3 which barrel member is'approximately the same diameter as the drill stem tubing. Connected to the lower end of the barrel member 3 by means of the adaptor member 4 is the 'core bit' 5. Applicants lay no claim to novelty for the core bit 5 and it may be of conventional design or any of a number of bits now in use for this purpose. Mounted within the barrel 3 and adapted to telescope therein is the core barrel 6. The core barrel 5 is guided and supported within the barrel 3 by the spider l and rests on the wear ring 8 in the bit member 5. The core barrel 6 is equipped with the conventional core catcher 9i which is a series of spring lingers that normally extend inwardly and are flexed outwardly to allow the core to pass into the core barrel. After the core is broken, the core catcher 9 holds the core within the core barrel 6.

'I'he lower end of the working barrel 3 has attached thereto a plate I which is held in place by means of the adaptor 4 screwed on the working barrel 3. 'I'he plate I 0 has a beveled valve seat II and a flap Valve I2 hinged to the plate I0. The valve I2 is held open by the core barrel S when the core barrel is seated on the wear ring 8.

The upper end of the core barrel is closed by the plug member I 3 which has tapered side walls I4 that seat in the replaceable valve seat I5 carried in the lower portion of the adaptor coupling member 2. The plug I3 has an extension I6 which receives` a. shing tool dropped within the drill stem to lift the core barrel upwardly. The core barrel 6 is constructed so that it may be extensible and is made of two telescoping sections II and I8. The two sections II and I8 rare held together in their non-extended position by means of the latch I9 and the two sections have a coil spring 20 therebetween tending to force the two sections apart. Upon upward movement of the core barrel the latch I9 will strike the beveled ring 2| in the working barrel 3 thus allowing the two sections to separate. The distance between latch I9 and beveled ring 2| is such that the bottom of the core barrel 6 will move above the valve I2 and thus allow that valve to seat before the latch I9 is disengaged from the sections. When latch I9 is dis-engaged, spring 29 forces the upper section I'I upwardly and the sides I4 on the plug I3 seat in the valve seat I5 and thus seal at this point. The lower section I8 is forced downwardly and seats on top of valve I2 and the weight of the whole core barrel keeps valve I2 closed.

The fishing device employed is shown in Figure 3 and comprises a wire line 22, an inertia member 23, jars- 24 and hook means 25. The hook means 25 are normally held in closed position by the leaf springs 26. When the hook means 25 contact the head portion I6, the arms spread outwardly until they have passed over the head portion and then the springs 26 make the connection secure. After the core barrel 6 has been pulled upwardly, to lremove the wire line 22, inertia member 23 and `iars 24 from the drill tubing, a shear pin 21 is provided which allows members 22, 23 and 24 to be pulled loose from the hookand raised to the surface of the ground.

In operation the working barrel 3 is on the surface of the ground or derrick floor. The core barrel is made ready by attaching the sections I'I and I8 together by latch4 I 9 and thus compressing spring 20. With the plate I0 and adaptor 4 along with bit attached thereto removed from the working barrel 3, the core barrel 6 is assembled within the working barre13. The plate I0 is then placed on the end of working barrel 3 and care-is taken to hold valve I2 open and insert the valve I2 between the working barrel 3 and core barrel 6. The adaptor 4 with bit 5 is then at.

tached and the core barrel seats on wear ring 8 and is spaced from the .working barrel 3 by the spacer 1. The device is now ready to be lowered into the well by adding sections of drill stem.

Drilling proceeds by rotating the drill stem which in turn rotates the whole assembly. Drilling mud is forced down the drill tubing and out around the drill bit. The drill bit cuts the core which passes upwardly through the core catcher 9 into the core barrel 6 and is retained in the core barrel by the core catcher 9. After the core has been cut, the drill stem may be swabbed if desired to cause a sample of the bottom hole fluid to enter outer barrel 3.

The fishing assembly is then lowered within the drill stem and into the outer barrel 3 where the grab hooks 25 engage the fishing neck I6. 'I'he core barrel 6 is then lifted upwardly with the lower end of the core barrel passing the top of flap valve I2. When this occurs, ap valve I2 closes and then latch I9 engages wedge ring 2I and allows sections II and I8 to separate under compressive force from the spring 20. The plug I3 is thus moved upwardly and the beveled walls I4 thereof seat on the valve seat I5 to close off the upper end of the chamber of the outer barrel 3. The lower end of the section I8 seats on the valve I2 and tends to keep this valve closed.

The shing assembly is then given a jerk to break shear pin 21, and the wire line 22, inertia member 23 and jars 24 are removed by being withdrawn from the drill stem.

The core barrel 6 and the outer barrel 3 are4V then brought to the surface in the usual manner of pulling any rotary drill stem. When the core enters core barrel 6 the fluid displaced from the core barrel flows to the outer barrel through a leak hole 28 in the top of the core barrel. Recovery of the core and contents of the outer' barrel 3 and core barrel 6 is the next step. The landing sub I is removed from the adaptor 2 and the iishing neck I6 is removed from the plug I3. A take-off connection is then inserted where the shing neck was removed and said take-off connection has a prong thereon to depress valve 29. The volatile constituents are removed from the core and placed in a pressure tight vessel. 'I'he adaptor 4 is then removed from the lower end of the 'outer barrel 3 and the liquid constituents are recovered after which the core is removed from the core barrel.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and

that various changes in the shape. size and arrangement of parts may be resorted to without departing from the spirit of our invention or the scope of the subjoined claims.

Having thus described our invention, We claim:

l. A pressure retaining mounted within a string of drill tubing comprising a barrel, a seat on the lower end of the tubing supporting the barrel, a flap valve in theldrill tubing through which the barrel passes, a bit on the end of the drill tubing to ing the sectional barrel member in collapsed relation, a'seat on the lower end of the tubing supporting the barrel, a'bit on the end of the drill tubing to cut the core, the core passing upwardly coring assembly cut the core, the core passing upwardly into the barrel member,v

into the barrel member, means for lifting the barrel upwardly after coring is completed, means on the drill tubing which unlatch the sections of the barrel in their upward movement, and means forcing the sections of the barrel apart into sealing engagement with the drill tubing.

3. A pressure retaining coring assembly mounted vwithin a string of drill tubing comprising a sectional barrel member, a seat on the lower end of the tubing supporting the barrel, a ap valve in the drill tubing through which the barrel passes, a bit on the end of the drill tubing to cut the core, the core passing upwardly into the barrel member, and means for lifting thebarrel upwardly past the flap valve after coring is completed.

-4. A pressure retaining coring assembly mounted within a string of drill tubing comprising a sectional barrel member, latch means holding the sectional barrel member in collapsed relation, a ilap valve in the drill tubing through tions into fully extended position,- latch means holding the sections of the barrel in collapsed position against the action of the spring, a ilap 4 valve inthe drill tubing through which the barrel passes, a seat on the lower end of the tubing supporting the barrel, a bit on the end of the drill tubing to cut the core, the core passing upwardly into the barrel member and means for lifting the barrel upwardly past the flap valve after coring is completed.

6. A pressure retaining coring assembly mounted within a string of drill tubing comprising a sectional barrel member, spring means between the sections of the barrel urging the sections into fully extended position, latch means holding the sections of the barrel in collapsed position against the action of the spring, a ap valve in the drill tubing through which the barrel passes, a seat on the lower end ofthe tubing supporting the barrel, a second seat portion in the tubing spaced from the iirst mentioned seat, a bit on the end of the drill tubing to cut the core, the core passing .upwardly 'into .the barrel member, means for lifting the barrel upwardly past the flap valve after coring is completed, and means in the tubing contacting the latch upon .upward movement of the barrel tov release the latch whereby the spring forces the sections of the barrel to expand. DONALD W. AULD.

LOUIS J. WEBER. 

